Dairy cows produce milk for about 10 months (or 305 days) before having another calf and being able to produce milk again. This is known as the lactation period.
In theory, 10 lactations are possible, though this is very unlikely due to low production. In fact, in the USA, the average herd life of Holstein cows, which is by far the most common dairy cow breed in the country, is fewer than 3 lactations.
On average, dairy cows produce milk for five to six years before being sent to slaughter, even though they are still fertile and able to produce milk until they are about 8-10 years old. This is because their milk production rate no longer becomes economically viable to justify their feed costs.
How Long Do Dairy Cows Produce Milk After Giving Birth?
Just like humans, cows are only able to produce milk after they have given birth. This is regardless of whether we are looking at a Holstein cow, Jersey cow, or any other breed. Production levels peak at around 40 to 60 days after calving and then steadily decline until milking is stopped at about 10 months.
As cows are unable to produce milk all the time, in order to keep on producing milk, dairy cows must give birth to one calf per year, who are sometimes given calf milk replacer. Typically, cows become pregnant with their first calf when they are one and a half years old. Thereafter, artificial insemination then occurs within three months of giving birth.
As cows produce milk for about 10 months, each cow has a two-month period of rest every 10 months. This period of time is known as “the dry period” and is used for cows to rest and prepare to give birth to another calf. During these two months, a farmer adjusts a cow’s diet to ensure that the right balance of nutrients is consumed to ensure a healthy birth.
How Often Are Dairy Cows Milked?
Dairy cows are milked two to three times a day. While the frequency of milking may vary from farm to farm and depends on the type of parlor used, the stage of lactation and milk yield, a consistent schedule is usually adhered to because the cows are most comfortable when they maintain a consistent milking routine.
What Happens Once a Dairy Cow is No Longer Able to Produce Milk?
Once a dairy cow is no longer able to produce milk, it is sent to slaughter. Compared to beef cows, dairy cows are usually pushed to their limits to meet high production demands, which means that their meat is of lower quality and sold for less money.
Dairy cow meat is therefore commonly found in cheaper products such as processed meat products. Approximately 20% of beef consumed in the USA comes from dairy cows.
The age a dairy cow lives to until sent to slaughter is most strongly correlated to their production levels. Generally, high production cows do not live as long as lower production cows, but they are more profitable.
How Much Milk Can Dairy Cows Produce?
40 years ago, milk production per cow was more than half of what it is today. Today, in the USA, the average dairy cow produces more than 7.5 gallons of milk per day. This is over seven times greater than the amount of milk a cow would produce if she were to only feed her calf.
Looked at another way, during the lactation period, a cow is able to produce is over 2,000 gallons of milk or about 37,000 glasses of milk!
What Happens to a Cow If You Don’t Milk It?
If a cow goes a long time without being milked, this can cause bruising, udder injury, sickness and even death as the milk builds up in her udder, causing it to become full, which can then result in infections. This only applies to dairy cows with high milk production and not beef cows.
Are Growth Hormones Used to Increase Cow Milk Production?
In the USA, approximately 17% of dairy cows are injected with artificial growth hormone, which is known as bovine somatotropin. This increases milk production by 11%–25%.
While the use of this artificial growth hormone is considered harmless to humans by the FDA, it is banned in many other countries, including Canada, Australia, New Zealand, and in parts of the European Union.